AMMAN, Jordan — In a rare display of unity, Jordan and Syria agreed Monday to reject "partial and unilateral" peace settlements with Israel.
The agreement, announced in Riyadh, Saudi Arabia, amounted to a virtual rejection by Jordan of recent suggestions from Israeli Prime Minister Shimon Peres that Israel and Jordan could negotiate a peace agreement directly without the participation of the Palestine Liberation Organization.
But the Jordanian-Syrian agreement was announced before Peres, addressing the U.N. General Assembly, formally offered to undertake direct negotiations with Amman and unilaterally declared that Israel no longer considers itself at war with Jordan.
There was no immediate Jordanian reaction to Peres' speech.
The Jordanian agreement with Syria appeared likely to place increasing pressure on PLO Chairman Yasser Arafat, with whom Jordan agreed last February to pursue a Mideast peace initiative. Arafat and Syria are bitter enemies, so any agreement between Syria and Jordan is likely to be viewed as undercutting Arafat's stature here.
The agreement was reached in Riyadh after two days of talks between Prime Minister Zaid Rifai of Jordan and his Syrian counterpart, Premier Abdel-Raouf Kasm.
The talks were held under the auspices of Saudi Crown Prince Abdullah, who heads an Arab committee charged with negotiating an end to the bitter feuding that has prevailed between Syria and Jordan since 1980.
Arab League Plan
According to a statement released by Abdullah, as reported by the Jordanian news agency Petra, the two sides agreed to pursue the peace plan adopted at an Arab League summit in Fez, Morocco, in September, 1982.
It said that a just peace should be achieved "within the framework of an international conference under United Nations auspices."
The eight-point Fez plan called for the creation of an independent Palestinian state with Jerusalem as its capital, a far tougher position than that envisaged in the Jordanian-PLO agreement reached last Feb. 11, which called for a Palestinian state in confederation with Jordan in the Israeli-occupied West Bank of the Jordan River.
The Jordanian-Syrian communique reiterated their commitment to Arab summit resolutions "in which Arab consensus was achieved," a clear attempt to exclude the results of the meeting held in Casablanca, Morocco, last August, which Syria boycotted. The Casablanca meeting gave a lukewarm endorsement to the Jordanian-PLO proposal.
The new statement quoted Abdullah as saying that Jordan and Syria agreed to the "rejection of partial and unilateral settlements with Israel."
After talks in Washington last week, the Israeli prime minister said he agreed with Reagan Administration officials that their immediate goal was to arrange a face-to-face meeting with Jordan's King Hussein. He said that such a meeting should be preceded by a statement of non-belligerency from Hussein.
On Monday, Peres followed this up in his U.N. speech by declaring an end to the state of war with Jordan and offering to visit Jordan this year to participate in a Mideast peace conference. "Let us talk," he said.
There was also widespread speculation in Israel that Peres had actually met Hussein in Paris in the last few days. When asked on Israeli radio if he could confirm or deny such a meeting, Israeli Foreign Minister Yitzhak Shamir said, "I can't confirm it."
The Jordanian-Syrian agreement comes at a time when King Hussein is believed to be increasingly irritated with Arafat. Both Hussein and Arafat have said they are reassessing their joint initiative.
Britain last week canceled a meeting with a joint Jordanian-PLO delegation, which included two representatives of the PLO's governing executive committee, after one official, Mohammed Milhem, refused to accept a statement that endorsed Israel's right to exist within its pre-1967 borders.
While PLO officials accused the British of introducing last-minute conditions, Hussein acknowledged that "we had a clear understanding with London" and that the British had acted honorably.
Achille Lauro Crisis
Western diplomats here believe that the crisis over the hijacked Italian cruise liner Achille Lauro effectively killed any chance for the PLO-Jordanian peace initiative in its present form.
Nonetheless, the statement released in Riyadh appeared to be a considerable victory for Syria's President Hafez Assad, who has opposed the Jordanian-PLO initiative from its inception.
The formulation that Syria and Jordan adopted, accepting the Fez plan and an international conference, is identical with Syria's position in recent years.
The communique said that Jordan and Syria agreed to continue their "constructive and brotherly dialogue" in Damascus and Amman.
The statement made no reference to another bone of contention between Syria and Jordan: Syria's demand that Hussein expel Syrians who oppose the Assad regime in Damascus.
There had been earlier signs of a thaw between Syria and Jordan. On Saturday, the famed Hejaz railway between Damascus and Amman, which was halted in 1983, quietly resumed service.